Method of making motor fuel and by-products



Patented Jan. 9, 1945 UNITED METHOD OF MAKING MOTOR FUEL AND BY-PRODUCTSJoseph Hidy James; Pittsburgh, Pa., assignor to Clarence P. Byrnes,trustee, Pittsburgh, Pa.

Application October 3, 1939, Serial No. 297,713

17 Claims.

My invention relates to the manufacture of motor fuel for internalcombustion motors and by-products from liquid hydrocarbons such aspetroleum fractions; and involves partial oxidation of mineral oil or afraction thereof and cracking as well as fractionating of the partialoxidation product.

One object of the invention is to reduce the cost of industrial productsmade from the par-' tial oxidation product. For example, in making motorfuels by cracking of the partial oxidation product, their cost isreduced by extracting from the product of partial oxidation valuablechemical products of higher value per liquid unit than such fuels. Thesechemical products are preferably prepared from a fraction or fractionsof the oxidation product of different average molecular weight than themotor fuel.

Another object is to better prepare the oxidation product for crackingto produce motor fuels; and another is to obtain cheaply and byrelatively simple steps a motor fuel of relatively high octane value orrating.

Another object is to utilize portions of the oxidation product not welladapted for motor fuels, by preparing valuable industrial productstherefrom.

In carrying out the process, mineral oil or a fraction thereof ispartially oxidized, preferably in my vapor-phase process, by vaporizing,mixing with a gas containing free oxygen, and passing through a hotreaction zone preferably in the presence of an oxidation catalyst.During this vapor-phase partial-oxidation step some incidental crackingoccurs and may be increased by increasing the temperature, the depth ofcatalyst if used, etc. The exit stream may be condensed andfractionated, and an intermediate portion may then be cracked, whileindustrial products may be extracted from the lighter fraction orportion. The heaviest portion or fraction or a part of it is preferablytreated to pro duce detergents as hereinafter explained. I thus reducethe cost of the cracked intermediate motor fuel fraction or portion,since highly valuable chemicals are produced from the lighter andheavier fractions.

The partial oxidation and cracking steps may be successive in eitherorder or substantially.

steps. The'-'figure of the drawing herein shows in ,the liquid phase, Ipreferably so grade the variables that a large percentage of alcoholsis, in the example shown in detail in the drawing obtained, as disclosedin my United States Patents 1,759,620 and 1,859,587, with relativelyless acids. The exit gas stream may be taken to and utilized in apolymerizing unit to make liquid motor fuel.

Following the "partial oxidation step on gas oil for example, thecondensed product is preferably treated to remove the free acids as, forexample, by saponification with lime. In this step calcium hydroxide isadded with Water (5% by volume of oil) and warmed to 80 C. for fourhours. The calcium soaps come out in the water layer in insoluble formand the acids are set free by treatment with a mineral acid such ashydrochloric acid. This step may, if desired, be combined withfractionation in accordance with United States Patent 1,948,161 to myassistant Bitler, the rough soaps being tapped out of the still; or thesoaps may be separated and the remainder then fractionally distilled inthe ordinary way. The acids may then be freed and recovered as freeacids, if desired, and these may be sulfonated and converted into soaps.

If it is desired to obtain chemical products from a lighter fraction, Iprefer as shown in the drawing to collect separately and cut out thefirst and lightest fraction up to about 10% of the total and boilingbelow about 200 C. This fraction may then be treated to obtain a goodsolvent preferably by dilute alcohol extraction in accordance with myUnited States Patents 1,782,963, 1,782,964, 1,835,600, or 1,894.,097. Inthis. case the oxidized oil after acid removal is distilled atatmospheric pressure to obtain a cut of about 10%; the extracting mediumused is preferably a mixture of ethyl alcohol'and water in theproportion of about alcohol and 40% water. This may be applied in anordinary extraction apparatus such as used for purifying lubricating oiland the volume of extraction mixture is about equal to that of the 10%cut. The alcohol and water mixture is then separated from the solvent bycareful fractionation distilling. The extractive medium is thenreturned. About 30% of this solvent stock fraction is obtained assolvent and the remaining may be added to the main body of oxidizedmaterial used as cracking stock.

If, as I prefer, the heavy end portions of the oxidized material are tobe made into chemical products, I preferably take this heaviestdistilled fraction of about 15% which is above C8 or C12 and vacuumdistil it. In this process about two-thirds becomes sulfate stock andthe residue of about one-third, which may remain as bottoms, may beadded to fuel oil.

In the example flow sheet of the drawing, an Engler distillation showedthe boiling range as follows, this showing when the 10% for solvent Thepercentages show the volume passing over. In the preparation of sulfatestock (disregarding the 3% taken out as solvent), the distillation isstopped at 85% by volume so that the material to be vacuum distilled isabove 343 C., distilling at atmospheric pressure. All above 343 C. isheavy ends which are vacuum distilled. Using a pressure of 5 centimetersof mercury the sulfation stock is distilled at approximately 80% underthe Engler above given or from 263 C. to 276 C. The remainder is notdistilled but is added to fuel oil.

The distilled-over portion is then treated with a polybasic acid of theinorganic type such as sulphuric acid, though other equivalent polybasicinorganic acids may be used such as boric acid, phosphoric acid, arsenicacid, and particularly those having three or more replaceable hydrogenatoms, as well as the corresponding pyro acids and thecorresponding ousinorganic acids such as phosphorous acid, arsenious acid, etc. Whensulphuric acid is used the treatment is preferably that set forth in myU. S. Patent No. 2,085,500 of June 29, 1937, from line 63, page 2, toline 39, page 3. This sulphonation step is now generally known. Theproduct is a mixture of heavier esters or alkyl acid salts or acidesters, in the range above C4 or C6 and preferably above Cs.

On sulphating or treating with a polybasic acid for wetters and fordetergents, and then neutralizing the alkyl acid salts such assulphates, the sulphate soaps such as sodium alkyl sulfates areproduced. The following is an example of sulfation used in the flowsheet diagram: Take 500 cc. of stock and 100 cc. petroleum ether(boiling under 90 C.) in a 1.5 L beaker. Surround the beaker withice-salt mixture as temperature must be kept at 0 C. Using 20% oleum anda good stirrer, drop the oleum slowly into the cooled oil; it will takemore than two hours, as the rate of oleum addition must be such that thetemperature does not rise, above zero C. A total of 166 cc. of the oleumis needed. After complete addition of oleum, stir (still keeping at zeroC.) for one hour longer. Add 200 g. cracked ice (about size of olivesand smaller),

stir for 15 minutes. When ice has melted add 40 g. of Glauber saltcrystals, and stir for 15 minutes. If necessary warm until emulsionbreaks. We have never had to heat about 50 C., and prefer not to go thathigh. Right here is where one must work as fast as possible as dilutemineral acid catalyzes the hydrolysis of the acid esters of sulfuricacid. Draw oif lower layer. The top layer is now ready to saponify.

Neutralization: formation of alkyl sodium sulfates or sulfate soaps Totop layer above, add cc. water and 400 cc. of the petroleum ether. Stirin pulverized soda ash until slightly on alkaline side. Make sure ofsaponification by stirring for onehalf to one hour longer, making otheradditions of soda if necessary. Add with stirring 25 cc. denaturedalcohol (formula 1) to facilitate separation. Three layers form. Lowest:contains saturated solution of sodium sulfate with the slight excess ofsodium carbonate. Intermediate: soaps in solution with part of theinorganic salts. Top: non-sulfatable oil plus the added petroleum ether.Draw off: test top layer for soap by extraction of a test sample with50:50 alcohol water medium, evaporating off alcohol and examining forsoap. If there is a sufficient amount of soap present, extract thiswhole layer with successive portions of 50:50 as above. This is usuallynot necessary. If it is done, the extracted soap solution must usuallybe washed with the petroleum ether to remove any oil. A test portion ofthe extracted soap having all the alcohol evaporated should give a clearwater solution, showing that all the oil has been removed.

The main soap solution layer above (the intermediate layer) is givensuccessive petroleum ether (under 90 C.) washes until any oil isremoved. This can be told by the color of the petroleum ether, andchecked by taking a few cc. of the soap solution for a test sample,evaporating off the alcohol and noting if the soap dissolves in hotwater without turbidity. If soap is recovered from the petroleum etherlayer above and it is free from oil it may be added to the main portionof the soap at this point.

The soap solution should now be evaporated carefully to a pastyconsistency, if the removal of the sodium sulfate is desired. Use about60 C. as the upper limit of temperature and evaporate with plenty of airblowing over the surface of the solution. The foregoing pasty solutionis now diluted with ten volumes of denatured alcohol which takes thesoaps into solution and throws out the sodium sulfate. Filter, andevaporate carefully to obtain the dry soaps. The yield of sulfate soapsbased on the sulfated oil used varies from 25% to 50% by weight.

In these steps the non-sulfatable oil remaining which is usually thelarger portion thereof is separated and added to the cracking stock.

The cracking stock is then subjected to a cracking operation or thermaldecomposing step either with or without a catalyst and with or withoutsuperatmospheric pressure, but preferably under moderate or heavypressure. This may be done either in the liquid phase or vapor phase orboth combined. In cracking, the range of the oxidized stock was from C.to 350 C.; the cracking pressure may be 250 lbs. per sq. in., thetemperature about 931 F., and the coil volume in cu. ft. above 750 F.per barrel throughput per dayabout .030. In this operation a high octanerating gasoline is produced; the gas produced may be polymerized intopolymer gasoline, and the remainder may be utilized as recycle stock towhich fresh oil (makeup) is added to go to the oxidizer. An example ofgases from cracking this oxidized mixture shows co2-2.3%, CO29.4%,H-2.4%, methane-l7.8%, ethane-12%, ethylene-l2.5%, propane6.6%,propylene10%, butanes2.6%, and pentanes4.4%. This analysis plainly showsthat this gas mixture is amenable to ordinary types of polymerizationused in gasoline forming. The above specific directions give one exampleof the process-that shown in the accompanying flow sheet drawing; andthe claims herein are not limited thereto.

In the figure of the drawing I show an example of one form of myprocess, giving approximate figures and proportions wherein 20,000barrels of gas oil are partially oxidized, preferably by my vapor phaseprocess, giving about 90% of condensed product. Of this about 50% goesinto motor fuel, about 14% into by-products, about 4% into gas loss,about 5% into fuel oil, and about into loss in oxidation, the remaindergoing to recycle stock.

Thus certain lighter and heavier oxygen derivatives of hydrocarbonsformed in the oxidation step may be made into industrial chemicalproducts of much higher value per unit than motor fuel, or any desiredproportion of the total may be passed on into the cracking step formaking motor fuel and other products. By using a bubble tower succeedingthe oxidizer, the exit stream therefrom may be fractionally condensedinto the desired fractions, which may then be treated as above recited.

A modification of the foregoing procedure is to remove the solvent fromthe total oxidized product just after the removal of the acids asoutlined above, but then take all the remainder of the oxidized oil,except the 5% heavy ends, to the cracking process. In all crackingprocesses, whether pyrolytic or catalytic, there is a broad fractionwhich runs in boiling points from the upper end of gasoline through tothe ordinary as oil end point. This is usually known as recycle stock,but for my by-product purposes, I may first sulfate either the wholefraction or preferably the heavier portion, making the usual sodiumalkyl sulfates or sulfate soaps. The nonsulfatable oil becomes therecycle stock in this modification. One advantage of this modificationis that the unsaturated compounds formed in the cracking operationbecome available for sulfation, thus increasing the sulfate soap yieldover that outlined in detail in the drawing.

The advantages of my invention result from the utilizing of differentportions of my oxidized product which are of different average molecularweight, for conversion into chemical products and liquid fuelsrespectively; and from the elasticity of operations thereby obtained.Depending upon the demand, prices, etc., the steps may be varied and theproportions produced for various industrial purposes. The cracked motorfuel product usually contains oxygen derivatives of hydrocarbons whichaid in burning qualities and value, while derivatives of other molecularweights are made into valuable chemical products.

The partial oxidation may be carried out either in the vapor phase orliquid phase or both, the fractionating may be carried out in differentways, the fractions may be varied as to end points, the acids may beremoved before fractionating,

or taken out of certain fractions after fractionating, the heaviestportions may be removed after cracking, and many other changes may bemade without departing from my invention.

I claim:

1. In the treatment of a product of the partial I oxidation of mineraloil containing non-aromatic hydrocarbons, the steps consisting ofpartially oxidizing mineral hydrocarbons in the presence of free oxygeninto a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids,fractionating the product, cracking a fraction and ing gases from thecracking step.

2. In the treatment of a product of the partial ing the liquid productinto fractions of different average molecular weights, extractingchemical products from a lighter fraction and applying a chemicalreagent to extract a chemical product from a heavier fraction remainingafter said extraction, adding parts of said fractions to an intermediatefraction, and cracking said combined fractions.

4. In the treatment of a product of the partial oxidation of mineral oilcontaining a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the liquid product, reacting with a chemicalto extract a chemical product from a lighter fraction, returning aremainder thereof after extraction to a fractionating step, and crackinga fraction resulting from further fractionating.

5. In the treatment of a product of the partial oxidation of mineral oilcontaining a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the product into at least three fractions,reacting with a chemical to extract a chemical product from a lighterfraction, returning a remainder thereof after extraction to afractionating step, removing a heavier fraction, and cracking anintermediate fraction.

6. In the treatment of a product of the partial oxidation of mineral oilcontaining a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the liquid product, reacting with a chemicalto extract a chemical product from a lighter fraction, returning aremainder thereof after extraction to a fractionating step, removing aheavier fraction, and extracting a chemical product from said heavierfraction.

'7. In the treatment of a product of the partial oxidation of mineraloil containing a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the liquid product, reacting with a chemicalto extract a chemical product from a lighter fraction,

returning a remainder thereof after extraction to a fractionating step,cracking a heavier fraction, and fractionating the product of saidcracking.

8. In the treatment of a product of the partialv oxidation of mineraloil containing a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the liquid product, extracting a chemicalproduct from a lighter fraction, returning a remainder thereof afterextraction to a fractionating step, cracking a, heavier fraction,fractionating the product, and extracting a chemical product from afraction obtained in the latter fractionating of the cracked fraction.

9. In the treatment of a product of the partial oxidation of mineral oilcontaining a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the product, reacting with a chemical toextract a chemical product from a fraction, adding the remainder of saidfraction to another fraction, cracking the combined portions thusobtained, extracting motor fuel from the cracked product, andreoxidizing a remainder from the latter extraction of motor fuel fromthe cracked product.

10. In the treatment of a product of the partial oxidation of mineraloil containing a plurality of different oxygen derivatives of aliphatichydrocarbons in the range from alcohols to oxygenated acids, the stepsconsisting of fractionating the product, reacting with a chemical toextract a chemical product from a lighter fraction, adding a remainderthereof after extraction to a heavier fraction, cracking the combinedportions, recovering motor fuel from the cracked product, andreoxidizing a remainder from said recovery.

11. In the treatment of a product of the partial oxidation of mineraloil, the steps consisting of removing a lighter portion, cracking aportion heavier than said lighter portion, and polymerizing bodiespassing ofi in gaseous state from the cracking step.

12. In the method of obtaining a plurality of different chemicalproducts from normally liquid partially oxidized petroleum containingoxygenated acids and other oxygen derivatives in the range from alcoholsto acids, the steps consisting of removing acids from substantially allportions thereof and fractionating the petroleum into at least threeportions, separating a lighter portion, recovering a chemical from saidlighter portion, separating a heavier portion, reacting it to recover achemical product therefrom, and cracking an intermediate portion.

13. In the method of obtaining a plurality of different chemicalproducts from normally liquid partially oxidized petroleum containingoxygenated acids and other oxygen derivatives in the range from alcoholsto acids, the steps consisting of first removing acids from saidproduct, then fractionating the product into at least three portions,separating a lighter portion, recovering a chemical from said lighterportion, separating a heavier portion, reacting it to recover a chemicalproduct'therefrom, and cracking an intermediate portion.

14. In the method of obtaining a plurality of different chemicalproducts from partially oxidized petroleum containing oxygenated acidsand other oxygen derivatives in the range from alcohols to acids, thesteps consisting of first removing acids from said product, thenfractionating the same into at least three portions, separating alighter portion, recovering a chemical from said lighter portion,separating a, heavier portion, reacting it to recover a chemical producttherefrom, and cracking an intermediate portion containing a part ofsaid heavier portion.

15. In the method of obtaining a plurality of different chemicalproducts from partially oxidized petroleum containing oxygenated acidsand other oxygen derivatives in the range from alcohols to acids, thesteps consisting of first removing acids from said product, thenfractionating the same into at least three portions, separating alighter portion, recovering a chemical from said lighter portion,separating a heavier portion, reacting it to recover a chemical producttherefrom, and cracking an intermediate portion containing parts of boththe lighter and heavier portions.

16. In the method of obtaining a plurality of different chemicalproducts from normally liquid partially oxidized petroleum containingoxygenated acids and other oxygen derivatives in the range from alcoholsto acids, the steps consisting of first removing acids from saidproduct, then fractionating the product into at least three portions,separating a lighter portion, recovering a solvent from said lighterportion, separating a heavier portion, reacting it to recover a chemicalproduct therefrom, and cracking an intermediate portion.

17. In the method of obtaining a plurality of difierent chemicalproducts from normally liquid partially oxidized petroleum containingoxygenated acids and other oxygen derivatives in the range from alcoholsto acids, the steps consisting of first removing acids from saidproduct, then fractionating the product into at least three portions,separating a lighter portion, recovering a chemical from said lighterportion, separating a heavier portion, reacting it to recover adetergent therefrom, and cracking an intermediate portion.

JOSEPH I-HDY JAMES.

